New roles for chemoreceptor paralogues in Drosophila

描述（由申请人提供）：这项工作的目的是确定冷检测的分子机制，使用果蝇作为模型。感觉系统在人类健康中起着关键作用。不仅人类感觉系统功能障碍与疾病有关，温度的检测对于人类疾病的昆虫媒介的生存和宿主寻找行为也很重要。目前，我们对昆虫温度检测的分子认识有限：昆虫冷受体尚未报道。我们的初步数据表明，两个离子型受体家族成员，IR 21 a和IR 25 a，参与冷感。离子型受体（IR）是无脊椎动物中iGluR的一个亚家族（果蝇有66个IR），已知其不作为谷氨酸依赖性突触传递的介质，而是作为酸和胺的化学受体。我们建议测试的假设，IR 21 a和IR 25 a的特定亚型驱动避冷作用在冷传感器的芒和/或唇瓣。使用细胞特异性救援实验，我们建议确定哪些IR 21 a和IR 25 a亚型介导避冷，并测试这些IR在冷传感器中的表达是否是必要的和/或需要避冷。我们还将测试IR 21 a和IR 25 a是否介导冷感。使用钙成像和电生理学的组合，我们将研究IR 21 a和IR 25 a的贡献冷传感器通过研究如何改变突变体中缺乏这些蛋白质的冷传感器的冷响应。我也将测试是否IR 21 a和IR 25 a的行为，形成一个冷受体的异位表达这些蛋白质在苍蝇和异源表达在青蛙卵母细胞和培养的哺乳动物细胞。这些研究将有助于对冷遇的理解和识别 对阐明所涉及的分子机制具有极其重要的意义。

DESCRIPTION (provided by applicant): This work aims to identify the molecular mechanisms of cold detection, using the fruit fly Drosophila melanogaster as a model. Sensory systems play key roles in human health. Not only is human sensory system dysfunction associated with disease, the detection of temperature is important for the survival and host-seeking behavior of insect vectors of human disease. At present, our molecular understanding of temperature detection in insects is limited: insect cold receptors have not been reported. Our preliminary data suggest two Ionotropic Receptor family members, IR21a and IR25a, are involved in cold sensing. Ionotropic receptors (IRs) are a subfamily of iGluRs in invertebrates (Drosophila has 66 IRs) known to act not as mediators of glutamate- dependent synaptic transmission, but as chemoreceptors for acids and amines. We are proposing to test the hypothesis that specific isoforms of IR21a and IR25a drive cold avoidance by acting in the cold sensors of the arista and/or labellum. Using cell-specific rescue experiments, we propose to determine which IR21a and IR25a isoforms mediate cold avoidance, and to test whether expression of these IRs in cold sensors is necessary and/or required for cold avoidance. We will also test if IR21a and IR25a mediate cold sensing. Using a combination of calcium imaging and electrophysiology, we will examine the contribution of IR21a and IR25a to cold sensing by examining how the cold-responsiveness of each set of cold sensors is altered in mutants lacking these proteins. I will also test whether IR21a and IR25a act forming a cold receptor by ectopic expression of these proteins in the fly and by heterologous expression in frog oocytes and in cultured mammalian cells. These studies will contribute for the understanding of cold-reception and the identification of the receptors will be extremely significant to elucidate the molecular mechanisms involved.